FWIW, both my wife and I took mefloquine for our last trip, and neither one of us had any problems with it. But it definitely has an eye-opening list of side effects that are possible (although they're supposedly more common in the dosage levels to treat malaria, rather than preventative). I'm not sure if the side effects are really more common than the official numbers as ralfp thinks, or whether it's just that you hear about them more because of the nature of the side effects. I'll have to admit though that at the time I was debating whether I really wanted to take it, especially since the area we were travelling in we probably didn't *really* need it, but I'm glad to know that we seem to tolerate it, because we'll need something again for a future trip.